Internal Carotid Artery Aplasia in a Patient With Nail-Patella Syndrome.

Nail-patella syndrome (NPS) is a rare disorder characterized by abnormal development of ectodermal and mesodermal tissues. Classically, NPS presents as a triad of nail dysplasia, dysplastic patellae, and bony exostoses of the ilia known as "iliac horns." Apart from dermatological and skeletal abnormalities, patients may also have involvement of ophthalmologic and renal systems. The underlying molecular etiology in NPS is the mutation of LMX1B homeobox gene which results in loss of function of its protein also called LMX1B, a DNA-binding protein belonging to the larger LIM-homeodomain transcription factor family. Normal LMX1B gene and protein function are essential for dorsalization of the vertebrate limb bud, development of anterior eye structures, skull formation, and differentiation and migration of neurons in the central nervous system. We report a case of confirmed NPS presenting with congenital aplasia of the internal carotid artery and believe this is the first report of cerebrovascular developmental abnormality associated with NPS.